The present invention relates to a novel microsize driving device utilizable for transportation of microsize materials or so as a linear driving device or a rotary driving device within a micrometer-order region as well as to a method for the preparation thereof.
A protein which is found in a living body and exhibits mobility function in itself, such as kinesin and myosin, is generally called a motor protein. Kinesin and myosin have an ability to drive fibrous proteins such as microtubules and actin along the fibrous axis thereof by utilizing the energy released when adenosine triphosphate (referred to as ATP hereinafter) is hydrolyzed. These fibrous proteins capable of moving are defined here as a track protein.
While kinesin and myosin have a molecular weight of 140 kDa and 500 kDa, respectively, the size of the force generating domains is very small to be 4×5 nm and 5×20 nm, respectively. In microtubules and actin, the fibrous structure is formed by the self-assembly of molecules having a diameter of several nm so that fibers having a length of several tens of micrometers can be formed by causing self-assembly of these molecules in vitro.
As to such motor protein molecules, it is known that movements in random directions are effected when they are adsorbed on the whole surface of a substrate and track proteins are disposed thereon and linear bilateral movements are caused when they are arranged on a linearly patterned layer of a fluorocarbon resin or methacrylic acid-based resin and track proteins are disposed thereon (see Japanese Journal of Applied Physics, volume 34, 1995, pages 3937–3941; Biophys. J., volume 72, 1997, pages 1997–2001; Proc. Natl. Acad. Sci., U.S.A., volume 83, 1986, pages 6272–6276 and Cell, volume 42, 1985, pages 39–50).
FIG. 1 is a schematic perspective illustration of a state in which a track 2 formed as a raise on a substrate 1 is provided with an arrangement layer 3 of such motor protein molecules and track proteins 4 are disposed further thereon.
It could be expected that, if the energy of movement generated between such a motor protein and a track protein could be taken out, the same could be utilized, for example, as a power source for transportation of a microsize body but two problems must be solved therefor.
The first problem is to inhibit disappearance of the track proteins disposed on the arrangement of the motor protein molecules arranged within the track 2 on the substrate 1. Namely, while it is the prior art that, as is shown in FIG. 1, the motor protein molecules are adsorbed on the tracks 2 formed from a fluorocarbon resin or a (meth)acrylic acid-based resin, these tracks 2 are formed as a raise on the substrate 1 so that the track proteins 4 disposed thereon eventually fall from the track 2 during movements unavoidably resulting in a decrease of the amount thereof in the lapse of time. Accordingly, it is essential to accomplish an improvement in order to maintain the movement with stability within the tracks 2 over a long time.
The second problem is how to control the moving direction of the track proteins. When the motor protein molecules are arranged on a linear track and the track proteins are disposed thereon by a conventional method, namely, the movement of the track proteins is in bilateral directions along the lengthwise direction of the track so that the kinetic energy of the individual molecules cannot be taken out for utilization as a driving power source due to cancellation among the individual molecules. It is accordingly necessary to control the movement in a single direction in order to accomplish utilization of the kinetic energy as a driving power source.
Absolutely no reports are available heretofore, however, on the attempts to solve the above mentioned two problems for track proteins to be driven by motor protein molecules.